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Archiva Zootechnica 11:2, 35-41, 2008
35
Lipid profile after alpha-linolenic acid (ALA) enriched
eggs diet: a study on healthy volunteers
Dana Manda1
Criste2, Tatiana Panaite2, Oana Popa1
1
, Liliana Ionescu1, Rodica
1
, Olga Ianas1
1
National Institute of Endocrinology "C.I.Parhon", Bucharest
National Research - Development Institute for Animal Biology and Nutrition, Balotesti
2
ABSTRACT
The correction of a subtle nutritional deficiency that may reduce the risk of
a future chronic disease is indeed a challenge. One of the most intriguing
current and future impacts on public health may come from a greater intake of
omega-3 fatty acids such as alpha-linolenic acid (ALA). We investigated the
effect of an increased amount of dietary a-linolenic acid (ALA) from enriched
eggs on the lipid profile and inflammatory markers in healthy volunteers. 62
subjects were voluntary enrolled after they gave their informed consent. They
were randomly assigned in either control or omega group. Control group
consumed normal eggs while omega group consumed eggs enriched in omega 3
fatty acids. The content of ALA in omega 3 eggs was 5 times greater than that
of control eggs. During the study, all subjects maintained their habitual diets
except that egg consumption. Each subject had to consume 6 eggs a week
during a 6-week period. Blood samples were collected at day 0 (baseline) and at
the end of the study. Triglycerides, cholesterol, HDL, LDL cholesterol, ApoA,
ApoB, CRP and fibrinogen were measured in serum samples. We compared the
measured values of the biochemical parameters at baseline and after egg
consumption both in control and omega group. Triglycerides were significantly
reduced in omega group (p=0.002) after ALA enriched eggs consumption but
not in control group. Fibrinogen level was significantly decreased (p<0.001) by
ALA enriched eggs consumption whereas in control group there were no
significant changes. No significant changes were found in the other parameters
of the lipid profile or CRP. In conclusion, the alpha-linolenic acid dietary
supplementation decreases tryglicerides and fibrinogen level. Alpha-linolenic
acid enriched eggs can be considered as functional food with beneficial effects
on human health.
Keywords: alpha-linolenic acid, eggs, diet, human health.
INTRODUCTION
An increasing number of physiological functions have been attributed to
omega-3 fatty acids, including calcium movement inside and outside the cell,
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Dana Manda et al.
muscle contraction and relaxation, clotting, regulation of digestive enzymes and
hormones, fertility, cell division and growth, brain development. Omega 3 fats
may protect against cardiovascular disease by lowering blood pressure and heart
rate, reducing serum triglycerides, inflammatory markers (Bhatnagar D, 2003)
and arrhythmias (Geelen A, 2004) and improving endothelial function, insulin
sensitivity and plaque stability (Thies F, 2003).
The major dietary sources of omega-3 fatty acids in are fish, fish oil,
vegetable oils, walnuts, wheat germ, and some dietary supplements (Das UN,
2006). The class of unsaturated fatty acids can be divided into monounsaturated
and polyunsaturated fatty acids. Monounsaturated fatty acids (the primary
constituents of olive and canola oils) contain only one double bond.
Polyunsaturated fatty acids (PUFAs) (the primary constituents of corn,
sunflower, flax seed and many other vegetable oils) contain more than one
double bond.
Mammalian cells can introduce double bonds into all positions on the fatty
acid chain except the n-3 and n-6 position. Thus, the short-chain alpha-linolenic
acid (ALA, chemical abbreviation: 18:3n-3) and linoleic acid (LA, chemical
abbreviation: 18:2n-6) are essential fatty acids. No other fatty acids found in
food are considered ‘essential’ for humans, because they can all be synthesized
from the short chain fatty acids.
Omega-3 and omega-6 fatty acids are not interconvertible in the human
body and are important components of practically all cell membranes. Whereas
cellular proteins are genetically determined, the polyunsaturated fatty acids
(PUFA) composition of all cell membranes is to a great extent dependent on the
dietary intake. Therefore appropriate amounts of dietary omega-6 and omega-3
fatty acids need to be considered in making dietary recommendations, and these
two classes of PUFAs should be distinguished because they are metabolically
and functionally distinct and have opposing physiological functions. Their
balance is important for homeostasis and normal development. The
metabolisms of fatty acids of the n-3 family and of the n-6 family (arachidonic
acid [20:4(n-6)]) are of particular interest because of the biological actions of
their metabolites (eicosanoids) in vivo. For example, eicosanoids derived from
arachidonic acid are pro-inflammatory and pro-aggregator agonists, whereas
those derived from n-3 PUFAs tend to inhibit platelet aggregation and be antiinflammatory (Simopoulos AP, 1991).
The correction of a subtle nutritional deficiency that may reduce the risk of
a future chronic disease is indeed a challenge. One of the most intriguing
current and future impacts on public health may come from a greater intake of
omega-3 fatty acids such as alpha-linolenic acid (ALA).
Objective: We investigated the effect of an increased amount of dietary alinolenic acid (ALA) from enriched eggs on the lipid profile and inflammatory
markers in healthy volunteers.
Archiva Zootechnica 11:2, 35-41, 2008
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MATERIAL AND METHODS
Subjects and methods
62 subjects were voluntarily enrolled after they gave their informed
consent. They were randomly assigned in either control (C), 31 subjects or
omega group (O), 31 subjects. Control group consumed normal eggs while
omega group consumed eggs enriched in omega 3 fatty acids. The content of
ALA in omega 3 eggs was 5 times greater than that of control eggs.
During the study, all subjects maintained their habitual diets except that egg
consumption. Each subject had to consume 6 eggs a week during a 6-week
period.
Blood samples were collected in the morning after a 12-h fast at day 0
(baseline) and at the end of the study. Aliquots of serum were obtained and
stored at -80 C.
Triglycerides, cholesterol, HDL, LDL cholesterol, ApoA, ApoB, CRP and
fibrinogen were measured in serum samples.
Total cholesterol, high-density lipoprotein (HDL) cholesterol, Apo A, Apo
B100, triglycerides and high-sensitive C-reactive protein were assessed using
commercial enzymatic tests (Roche Diagnostics, Mannheim, Germany).
Fibrinogen was assayed by a quantitative method. Briefly, the blood sample
taken on Na citrate 3.81% is centrifuged at 2000 rpm, 10 min. 2 ml of resulted
plasma is mixed with 2 ml CaCl2 0.025 M and incubated at 37°C, in a water
bath for 30 min. The resulted gel is washed with distilled water, ethanol,
ether/acetone and is air dried for 24 h. The product is weighted and represents
the fibrinogen quantity.
Intervention
The ALA enriched egg was obtained by the National Research Development Institute for Animal Biology and Nutrition by feeding the lying
hens with diets enriched in vegetal oils and flax seeds. To produce linolenic acid
(omega-3 polyunsaturated fatty acid)-rich eggs the layers received a compound
feed based on corn, wheat, soybean meal, corn gluten, full fat soy and flax
seeds. Table 1 shows the quality indices of the compound feed.
Table 1
Metabolisable energy MJ / kg
Crude protein, %
Ether extractives, %
Fiber, %
Methionine, %
Methionine + cystine, %
Lysine, %
Calcium, g%
Available phosphorus, g%
Linoleic acid, %
Linolenic acid, %
11.85 ± 2.00
18.33 ± 2.00
7.03 ± 2.00
4.66 ± 2.00
0.41 ± 2.00
0.75 ± 2.00
0.94 ± 2.00
3.6 ± 0.60
0.34 ± 0.50
3.85 ± 0.50
0.46 ± 0.50
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Dana Manda et al.
The subjects were randomized to control or ALA enriched eggs
consumption. During the study, all subjects maintained their habitual diets
except that egg consumption.
RESULTS AND DISCUSSION
Omega-3 enriched egg
The fat composition of the eggs used in this study is presented in figures 1
and 2.
The omega-3 egg has a higher content of saturated fatty acids (33.74% vs.
26.17%) and a reduced content of monounsaturated fatty acids (45.04% vs.
38.63%). The polyunsaturated fatty acids content is reduced by 1.18%. The alfa
linolenic acid content was 4.74 times greater in omega-3 egg as compared to
control egg (2.65 g/100 g fat vs. 0.56 g/100 g fat) as is shown in figure 3.
Fig. 1 Fat composition of control egg
Fig. 2 Fat composition of omega-3 egg
26%
29%
28%
34%
38%
45%
Saturated
Saturated
Monounsaturated
Monounsaturated
Polyunsaturated
Polyunsaturated
Fig. 3 Alfa linolenic acid(C18: 3n-3)
content of egg yolk
2.65
3
g/100 g total fat
Fig. 4 Age distribution of the subjects
2.5
4, 7%
3, 5%
11, 18%
13, 21%
2
1.5
1
0.56
9, 15%
21, 34%
0.5
0
Control
Omega -3
20
30
40
50
60
More
Archiva Zootechnica 11:2, 35-41, 2008
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Table 2 presents the age and BMI of the two groups expressed as mean
±ES. There were not significant differences between study groups. Figure 4
shows the age distribution of the subjects.
Table 2 Subjects characteristics
Control (n=31)
Age, yrs
37.9±5.55
BMI, kg/m2
22.70±1.21
Omega 3 (n=31)
38.83±4.07
23.67±1.06
Tables 3 and 4 show the values of the biochemical and inflammatory
markers at the initial and final visit in control and omega-3 group, respectively.
We compared the measured values of the biochemical parameters at
baseline and after egg consumption both in control and omega group.
Triglycerides were significantly reduced in omega group (p=0.002) after
omega-3 enriched eggs consumption but not in control group. Fibrinogen level
was significantly decreased (p<0.001) by omega-3 enriched eggs consumption
whereas in control group there were no significant changes. No significantly
changes were found in the other parameters of the lipid profile or CRP.
Table 3. The effect of control egg on biochemical profile and inflammatory markers
Analyt
UM Initial, M
±ES
Final, M
±ES
Creatinine
mg/dl
0.993
0.095
0.945
0.115
Alkaline phosphatase
U/l
93.250
13.223
66.875
6.607
Calcium
mg/dl
9.300
0.182
9.119
0.219
Cholesterol
mg/dl
200.250
8.976
187.750
13.667
Triglycerides
mg/dl
96.125
19.224
95.125
20.390
Uric acid
mg/dl
3.569
0.428
4.999
0.633
Magnezium
mg/dl
1.969
0.068
2.099
0.096
AST
U/l
13.950
1.100
20.200
2.045
ALT
U/l
16.663
3.370
23.286
6.070
Glucose
mg/dl
88.125
4.015
87.000
3.352
UREA
mg/dl
34.550
7.190
32.671
10.629
Phosphorus
mg/dl
3.611
0.218
3.863
0.220
Total protein
g/dl
7.178
0.104
7.306
0.139
HDL
mg/dl
55.463
2.529
57.400
3.804
LDL
mg/dl
118.500
9.816
114.750
11.498
apoB
mg/dl
86.100
6.756
82.813
6.314
apoA1
mg/dl
166.438
4.295
150.600
4.800
CRP(C-reactive protein) mg/dl
0.185
0.066
0.328
0.139
Fibrinogen
mg/dl
393.62
46.24
456.12
53.65
P
ns
0.010
ns
ns
ns
0.002
ns
0.001
ns
ns
ns
ns
ns
ns
ns
ns
0.008
ns
ns
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Dana Manda et al.
Table 4. The effect of omega-3 egg on biochemical profile and inflammatory markers
Analyt
UM Initial, M
±ES
Final, M
±ES
P
Creatinine
mg/dl 0.820
0.027
0.832
0.023
ns
Alkaline phosphatase
U/l
60.300
4.182
65.300
3.004
0.040
Calcium
mg/dl 9.395
0.087
9.238
0.061
ns
Cholesterol
mg/dl 199.433
7.823
207.433 10.870
ns
Triglycerides
mg/dl 112.400 13.215
90.967
10.437
0.002
Uric acid
mg/dl 3.810
0.192
5.311
0.300
<0.001
Magnezium
mg/dl 1.936
0.037
1.979
0.043
ns
AST
U/l
16.300
1.199
22.433
1.552
<0.001
ALT
U/l
20.900
2.570
14.853
1.855
<0.001
Glucose
mg/dl 91.467
1.789
93.300
1.627
ns
UREA
mg/dl 25.690
1.800
33.493
1.424
<0.001
Phosphorus
mg/dl 3.559
0.081
3.754
0.104
0.019
Total protein
g/dl
7.350
0.062
7.526
0.074
0.005
HDL
mg/dl 51.013
2.263
51.907
2.244
ns
LDL
mg/dl 121.467
8.274
128.900
8.840
ns
apoB
mg/dl 89.837
5.756
89.013
6.170
ns
apoA1
mg/dl 155.443
4.112
154.980
5.000
ns
CRP(C-reactive protein) mg/dl 0.378
0.13
0.378
0.147
ns
Fibrinogen
mg/dl
436
23.68
308.2
22.64
<0.001
DISCUSSIONS
Egg nutritional value can be easily influenced by the structure and
composition of hen’s food. Polyunsaturated fatty acids are essential nutrients for
human health. The animal nutritionists modified the fat composition of the egg
yolk and obtain an omega.
Correcting low levels of PUFAs and the balance between pro-inflammatory
and anti-inflammatory molecules may aid in the prevention of cardiovascular
and other inflammatory diseases ( Das UN, 2008).
Previous studies showed that biochemical and behavioral abnormalities due
to low-levels of omega-3 fatty acids are partially reversed by a dietary
supplement as omega-3-rich egg yolk extracts (Bourre JM, 2004).
We tested the effect of consumption of this egg on healthy volunteers in a
blind randomized study.
Our outcomes were the trygliceride levels, apo B and inflammatory
markers, fibrinogen and C-reactive protein.
The results showed that omega-3 egg consumption on a dose of 6 eggs a
week for 6 weeks significantly decreased the tryglicerides level of the
intervention group. No significant changes were found in Apo B. We also found
Archiva Zootechnica 11:2, 35-41, 2008
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a significant reduction of fibrinogen level in the omega-3 group, but no effect
on CRP.
CONCLUSIONS
The omega-3 enriched egg (2.65 g/100 g fat) consumed in a dose of 6 eggs
a week for 6 weeks significantly reduced the tryglicerides and fibrinogen level
egg a functional food with benefic effects on human health.
ACKNOWLEDGEMENTS: This work has been done under the contract
BIOTECH nr. 22/2005.
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Geelen A, Brouwer IA, Zock PL, Katan MB. Antiarrhythmic effects of n-3 fatty
acids: evidence from human studies. Curr Opin Lipidol 2004;15:25-30.
Thies F, Garry JM, Yaqoob P, Rerkasm K, Williams J, Shearman CP, et al.
Association of n-3 polyunsaturated fatty acids with stability of
atherosclerotic plaques: a randomised controlled trial. Lancet 2003;361:47785.
Das UN, Essential fatty acids: Biochemistry, physiology and pathology, Biotech
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Simopoulos AP. Omega-3 fatty acids in health and disease and in growth and
development. Am J Clin Nutr 1991; 54:438–63.
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